When I had the awning motor replaced last fall, I also wanted the one arm retrofitted with the adjustable one. I was told that my model would not accept that. When it did work, I did not have a problem with water pooling on it, but it always seemed to drain off the end in front of the door, even though the trailer was level.
I don't know what could be "redesigned" on it, but one of the minor annoyances is that when it rains and there's a wind, the door is not protected very well by the awning. With the slide near the door, there isn't a lot of room to move it further towards the rear of the trailer.